1. Field of the Invention
This invention relates to a single-reel type tape cartridge for use with magnetic recording-reproducing apparatus and, more particularly, to improvements in the tape leader of a tape cartridge of the character.
2. Prior Art
Single-reel type tape cartridges are extensively used in computer backup and other data storage applications for safekeeping. With a tape cartridge of the type, a leader tape or leader member attached to the outer end of a magnetic tape is drawn out by a drawing-out member provided in a magnetic recording-reproducing apparatus (hereinafter referred to as a xe2x80x9crecorderxe2x80x9d) or drive, the tape is led through passages in the recorder, and the tape end is fixed to the hub of another reel resident in the recorder. Upon conclusion of recording or playback operation the tape is driven backward and withdrawn into the cartridge, until the leader tape is reset in the original position in the cartridge.
Typical leader members for conventional single-reel type tape cartridges include one (disclosed, e.g., in Japanese Patent Application Kokai No. 58-169380) which comprises a pin, block, etc. secured to a tape end to be caught by a tape drawing-out member of a recorder. Another type uses a leader tape of relatively tough, elastic material which is connected to a magnetic tape end and has a hole at its own outer end adapted to be engaged with a corresponding hook of a drawing-out member of a recorder which too is formed of a relatively tough, elastic material (Japanese Patent Application Kokai No. 62-502641).
FIG. 5 is an exploded view of a single-reel type cartridge 103 using the technique disclosed in the above-mentioned Patent Application Kokai No. 62-502641. A housing of the cartridge composed of an upper half casing 101 and a lower half casing 102 is shown containing a single tape reel 107 which has an upper flange 104 and a lower flange 105, the tape reel 107 being normally biased toward the lower casing 102 by a compression spring 108. A leader tape 109 is spliced to the outer end of a length of magnetic tape 106 wound round a hub (not shown) of the upper flange 104 of the tape reel 107. The tape reel 107 has a bearing (not shown) on a ring which is press fitted in an annular recess (not shown) formed in the center of the upper flange 104. With a reel shaft (not shown) fitted in the bearing, the reel can revolve around the shaft. The upper flange 104 of the tape reel 107 has a serration 114 formed along its circumference. On the other hand, a pair of brake members 112, 113 are provided on the inner surface 101a of the upper casing 101 and are normally biased toward the serration 114 by torsion coil springs 110, 111, with cogs 115, 116, respectively, of the brake members 112, 112 in mesh with the serration 114 to keep the tape reel from revolution when the cartridge is not in use. When the cartridge is on standby the magnetic tape 106 is fully wound up on the tape reel 107, and an engaging hole formed at the end of the leader tape 109 is engaged with a hook 117 located close to a side wall of the cartridge housing 103. An opening 120 through which the magnetic tape 106 is drawn out from the cartridge housing 103 is normally closed by a lid 118 which is openable with respect to the cartridge housing.
As the cartridge is loaded into a recorder for use, the brake members 112, 113 are automatically set free and the tape reel 107 is lifted against the urging of the compression spring 108 to a position free to turn. At the same time, the lid 118 is opened by means provided for that purpose in the recorder.
The tape drawing-out member of the recorder then enters the housing through the opening to be engaged with the hole of the leader tape 109 and draws out the magnetic tape together with the leader tape in the manner described above, so that the tape is threaded in the route within the recorder.
The leader tape 109 is made using a thick spring sheet of tough synthetic resin such as polyethylene terephthalate (PET). As FIG. 6 indicates, a hole 120 is formed at the end of the tape so as to be engaged with a tab 121 (serving as a hook) formed at the end of a tape drawing-out member 122 of the recorder. The hole 120 has an angular cutout 123 to ensure positive engagement with the tab 121, with a neck of the drawing-out member that supports the tab 121 fitted in the cutout. FIG. 6 shows a sequence of the stages (a), (b), and (c) in which the drawing-out member 122 that gains entrance into the cartridge is progressively engaged with the leader tape 109.
The tape drawing-out mechanisms of the prior art present the following problems. The tape drawing-out member 122 of the recorder, as shown in FIG. 6, is in the form of a tape connected to a reel provided in the recorder, with the tape end having the tab 121 adapted to be engaged with the hole 120 of the leader tape in the tape cartridge. Since the drawing-out member 122 of the recorder and the end portions of the leader tape 109 are both tape-shaped, they are susceptible to curling. When the both curl, the tape drawing-out member 122 of the recorder becomes sometimes unable to engage the leader tape 109 of the cartridge loaded in the recorder.
On the other hand, direct coupling of the end of a magnetic tape to a tough leader member without. the aid of a leader tape would stabilize the actions of drawing out and drawing in of the magnetic tape. However, a somewhat complex structure of the leader member, unlike a PET one, involves difficulties in assembling during the course of cartridge manufacture. The present invention is aimed at providing a stabilized, solid leader of a structure which lends itself to more simplified manufacturing process than heretofore.
Such a leader member has an additional problem. As illustrated in FIG. 14, it comprises a center pin member 91 in the form of a pin on which a tape end is wound and secured in place by clamping, and a pair of engaging members 92-1, 92-2 fixed at one ends, respectively, to the upper and lower ends of the pin member. On the sides of the engaging members 92-1, 92-2 facing each other, there are formed engaging recesses 94-1, 94-2 in mirror symmetry adapted to engage a pin or hook of a drawing-out member of a recorder. The center pin member 91 is a solid, slender member made of metal and is fitted at both ends in blind holes formed at one ends of the engaging members 92-1, 92-2 both made of plastic.
The leader of the structure described has drawbacks. The center pin member 91 is not always fitted evenly and to the same depth in the blind holes of the engaging members 92-1, 92-2, with the result that the distance between the engaging members is inconstant and the variable dimensional relationship with the drawing-out member of a recorder leads to inadequate cartridge performance. When uneven forces are applied to the portions of the engaging members 92-1, 92-2 connected to the center pin member 91, the pin member can sometimes. turn within the blind holes and hamper positive action of the leader. The present invention is aimed at providing a tough leader of stable action with a structure enhanced in dimensional accuracy and which lends itself to more simplified manufacturing process than heretofore.
The present invention provides a tape cartridge including a single tape reel around which a length of magnetic tape is wound and which is turnably held within a housing, the beginning of the tape being fixed to a leader so that it can be drawn out through an opening formed in the housing by a tape drawing-out member of a recorder which has a pin-like or hooked end capable of engaging the tape end, said leader comprising a center part (pin-like member) on which the beginning of the tape is wound and a pair of engaging members joined to the upper and lower ends of the member so as to engage the tape drawing-out member of the recorder, said engaging members having a plurality of recesses each for engaging the drawing-out member. Thus the engaging members can consist of members identical in structure.
The engaging members are elongated tabs of the same structure either formed with engaging recesses in both end portions on one sides facing each other, the recesses having guide slopes extending therefrom toward the center where the two recesses meet, or formed with engaging recesses on both sides thereof in such configurations that the recesses on the sides facing each other are in mirror symmetry, said tabs having through holes formed close to the both ends thereof to receive the both ends of the center pin member to which a tape end is to be fixed.
In another aspect of the invention the cartridge includes a single tape reel around which a length of magnetic tape is wound and which is turnably held within a housing, the beginning of the tape being fixed to a leader so that it can be drawn out through an opening formed in the housing by a tape drawing-out member of a recorder which has an end capable of engaging the tape end. Here the leader comprises a center pin member on which the beginning of the tape is wound and a pair of engaging members joined to the upper and lower ends of the pin member so as to engage the tape drawing-out member of the recorder, said center pin member having position-confining portions formed close to its both ends to confine the positions of the engaging members.
The position-confining portions are shoulders or flanges that limit the depth of fitting of the center member into the engaging members or alternatively the portions have profile shapes in cross section so as to confine the positions in the turning direction of the engaging members.
Preferably, the position-confining portions are shoulders or flanges that limit the depth of fitting of the center member into the engaging members and have profile shapes in cross section so as to confine the positions in the turning direction of the engaging members.
In yet another aspect of the invention, the center pin member has arrays of several annulets formed at both ends, each in a thread-like formation, to be fitted in the engaging members.
The flanges or shoulders formed close to the both ends of the center pin member define the distance between the two engaging members when the both ends of the center pin member are fitted in the holes formed in the engaging members, since the outer sides or shoulders engage the opposing sides of the engaging members in the assembled state. The proper control of the spacing between the engaging members thus achieved enhances the dimensional accuracy of the leader and ensures optimum performance of the tape cartridge. The presence of flanges increases the support to the engaging members, allowing them to be less susceptible to deformation or distortion than otherwise.
In the embodiments where the both ends of the center pin have non-circular shapes in cross section, the engaging members are kept from turning around the pin and proper performance of the tape cartridge is ensured.
Where the center pin member has arrays of several annulets formed at both ends, each in a thread-like formation, the pin member attains a broader area of contact with the engaging members, and mutual bite enables the members to maintain a constant engaging relation.